Control mechanism



March 17, 1953 w. DE l.. BERRY Erm. 2,632,122

" CONTROL MECHANISM Filed sept. s, 1946 2 SHEETS- SHEET 1 March 17, 1953w. DE l.. BERRY Erm.

CONTROL MECHANISM Filed Sept. 3, 1946 2 SHEETS- SHEET 2 Patented Mar.17, 1953 UNITED STATES PATENT OFFICE V2,632,122 lcoNrRoLl MEcHANIsM tion.of ADelaware 4'Application September 3, 1946, SerialNo. 694,644

(Cl. S10-93) 5 Claims. 1

This inventionfrelates toza 4control system and mores-specifically to asystem for controlling the operation of a motor driven press welder. Inthe voperation ofthat Vclass of heavy machinery suchas punch pressesvand press'welders which perform a pressing, stamping or clampingoperation a heavy ram is provided which is moved with respect torastationary platten. vConventional drivingmeans for the ram in thesemachines has heretoforebeen in the form of a large heavy iiywheel thatis driven by the motor and suddenly clutched to the driving means forthe ram bymeans of a jawk clutch. This causes high initial stresses inthe parts'and attendant noise and vibration. Italso Vmakesthe serviceproblem a major one. In l,order to eliminate the problems attendant suchconstruction and provide a smooth rapid acceleration of the ram it isproposed to utilizean electromagnetic clutch between the ywheel and theram drive so that there will 'be no direct mechanical connectionbetweenv parts which will be driven by a magnetic flux interlinkage.

It is therefore anobject of our invention to provide a control systemfor an electromagnetic drive for heavy machines. l

V,It is a further object of our invention to provide a control systemfor .an .electromagnetic clutch and brake for heavy machines.

It is a still further object of our invention to provide .a controlsystem for an..electromag neticdrivefor press Welding machines.

With these and other yobjects in view which will .become apparent .as.the specication proceeds, .our invention .will be best understood 1 asindicated by-arrows with similar four lines at-the top of Figure lA.

Figure 2 is a diagrammatic showing of the phased mechanical operation ofthe cam operated switches.

Figure' isa schematic diagram of the drive between the motor andrvmovable machine part.

Inasmuch'as each relay coil when energized actuates a plurality ofswitchcontacts either to open or close the same, it would be confusing toshow-'on the drawings the connections'between each rrelayactuatingcoiland its associated -contacts and soforpurposes of thisapplicationthe relay coils will be designated by letters, such for:example as A and the contacts actuated thereby by the same letters plusidentifying numerals such as AI and A2 etc., depending upon the numberof contacts actuated thereby.

Referring now more specifically to the circuit, there is shown a threephase power supply,rlines 2, 4.and 6 connected to a main control switch8, three input conductors,'lines I0, t2 and Yi4 being connected to theopposite side of the switch. Line I0 terminates in a pair of parallelconductors ISand vI8 which :are in turn connected to kone terminal .20of the three phase driving motor 22. In eachof the lines iE and i8 thereis a switch vFI and'RI respectively. Lines I2-and I4 arecross-'connected vby lines 24 and 26, which connections'have.seriallyincorporated therein switches F2 and F3 respectively. seriallyinterposedin lines I2 and I4 are switches R2 andR3, line i2 beingconnected to terminal 23 and line iI4 to terminal 3Ilof motor 22.Connected across lines i2 and I4 bylines 36 and -38 is primary 32 oftransformer 34. This. is a power transformer which provides thenecessary energy for the various actuating relays. Lines 36 and 38 areconnectedahead of the various switches F2, F3,1R2, R3 so that thetransformer will Vbe energized assoon as the main switch 8 is closed.Power line 40 is connected to line l2 between these switches andthemotor 22 and the associated power line 42 is connected to line I4 inlike manner. These latter lines therefore 4are not energizedunlesseither the series F `switches or the series R switches .are energized.-It will thus be obvious that as soon ,as the main power switch isclosed the motor will be energized to run in one direction by theclosure of the F series switches, or forward, or it may beenergized torotate in the opposite direction or reverse by the closure of the Rseries switches.

Secondary 44 of transformer 34 has line 45 connectedto one terminal and48 connected to the opposite to provide lower voltage power leads thanlines 40-42, to provide current for the various relays and furtherswitches. Directly connected across between these lines is an indicatorlamp- 50 which indicates to the operator whether or not the power supplyis energized. Directly connected in series relation between. lines 46vand 48 are a series of control switches and energizing coils forcontrolling the forward andreverse contacts F and R` which include a'switch 52, a'stop `switch 5.4, a manually closed `switch 56 which theoperator closes to energize the motor 22 in a forward direction, anormally closed contact R4, relay coil F and a normally closed contact58 which is thermally controlled by motor temperature and is operated bycoils 60 in the motor line. Thus if the temperature of the motor exceedsa certain Value this safety switch 58 will open. It will thus be obviousthat switches 52, 54, R4 and 58 under normal conditions Would be closedand therefore when the operator depresses switch 56, relay coil F willbe energized to close the F series contacts and energize the motor 22 torotate in a forward direction. In shunt around the switch 55 is anormally open contact F4 which is closed upon the energizatien of the Fcoil to maintain coil F energized but permit release of switch 55.

In parallel te that portion of the circuit just Idescribed includingswitch 5o, contact R4 and relay coil F is a second circuit forcontrolling f the reverse rotation coil R which has in series with it acontact F5 which is closed when relay vcoil F is de-energized, a reverseswitch 6I operated by the operator and a similar hold in shunt switch R5which ley-passes manual switch 6l. Through this circuit relay R can 'bevenergized by the manual closure of switch El which in turn actuates allthe R contacts and causes the motor to run in a reverse direction. Atthis point it will be obvious that there is provided f conventionalswitching means for a three-phase motor to cause the same to rotate ineither one of two desired directions.

This motor is mechanically connected to a iiywheel which must be placedin spaced driving relation with some means en the shaft of the press sothat the same will operate. This is accomplished through magnetic iiuxclutching means between a drum on the press shaft and this flywheel.

The control for the magnetic clutching means will new be described.Switch 62 is directly cennected to line 4o for power and is operated ormaintained in normally closed position by air lpressure in a line (notshown) which provides air to booster cylinders to give the press aninitial push to start the same. Thus, under normal conditions thisswitch would be closed as long as air pressure is provided to thecylinders. A second switch B4 is connected in series with the switch 62and also is normally closed by :air pressure, 4but in this instance itis by the air pressure provided to the solenoid operated air brake sothat the device will not operate unless air is being provided to thebrake system. Further in the series connection with the two switches t2and E4 is a fuse 65. A series of emergency stop buttons 63, lo, l2 and'i4 next fellow in series relation but placed, of course, in variousconvenient places around the machine and are normally closed but can beopened te deenergize the whole system if the necessity arises.

Connected to the last of the emergency switch buttons is a relay contactHI which is opened upon deenergizatien and is controlled by the relayIcoil H which is itself connected across power lines 46 and 48 and ha-sin series there-y with only the inch-run switch I5. It will be obviousthat when this switch is moved to the position shown er run position therelay coil I-I will -be energized, but whe-n it is moved to its uppercontact it relay coil I-I will be deenergized and the machine will becapable of inching operation only which will be described. In

r. continued series relation there is connected contact R5 which isclosed when the relay coil R is deenergized and opened upon energizationof relay coil R, therefore when the motor 22 is running in reversedirection this circuit may not be energized. Line 86 is connected at apoint between switch I4 and contact HI and extends to contacter Cl whichis in turn serially connected with lcontacter Si and relay coil E, theopposite terminal of which is connected to power line 48. Coil E is therelay control coil for the solenoid operated mechanical brake.

Line 82 is connected at a point between centactors Hl and R8 and extendsto normally closed contacter LSS which is operated by one of a series ofsynchronously driven mechanical cams which appear in Fig. 2 and Whoserelationship is adjustable and will be later described in more detail.Contacter LS@ is in turn serially connected with contacter L53 andcontacter E3 which is opened upon deenergization of coil E and closedupon energization thereof. Connected to line Bil is a normally closedcontacter H2 which is opened whenever relay H is energized, which underall normal conditions is when the switch 'l5 is in run position. Inse-ries with contacter H2 is a manually operated switch 34 which is theinch operation switch. In other words, when switch lo is moved tocontact point 18, the operator may then inch the machine along byclosing switch 8a and opening it when the machine has proceeded to thedesired point. Continuing in serial relation to switches H2 and 84 isswitch LI which is controlled by the re- E lay coil L which in turn isdirectly connected across the power lines 45 and 48 and has in seriestherewith only a time delay operated switch This is cent-rolled by an4electronic thermal relay 88 in circuit with the power tubes 96 and 92which provide current for the magnetic brake and clutch and thisprevents the operation of the whole circuit until the tubes have had anopportunity to heat up.

Continuing in the series relation with the main control line are aseries of what is known as run buttons or manually operated switches 94,the number depending upon the number of operators which the machine iste have, two buttons being provided per operator. These switches arenormally biased to upper position as shown and when in that positionclose the circuit through relay coil A to -power line 48. When, however,they are in depressed position they tend to complete a circuit throughrelay coil B. In series relation, however, to the circuit for relay coilB there is a second contacter L2 operated by coil L which maintains theswitch L2 closed during the running period of the machine. Also inseries relation to coil B is a contacter Al which is controlled by relaycoil A and is closed when this coil is energized. To the left of theserie-s of switches operated by the run buttons in this circuit is aswitch contacter Ml which is closed upon deenergization but opens uponenergization of the relay coil M which is the weld cycle initiatingrelay the intent being to maintain this circuit open when the weldingcontrol is dominating and `actually 4performing welds so that the pressmotor may not be moved at this time.

A conductive line sa is connected between switches Re and 94 and extendste a cam operated switch L52, the opposite side of which is connected toline 38, which in turn extends to an intermediate point .betweenswitches BI ,and B2. In shuntrelation around the cambperatedswitch LS2isa secondcam operated switch LS'|. -Also connected to line 96 is aVcontactor NI which is controlled lby relay lcoil N and closes uponenergization thereof. Inseries with this switch is a pressure actuatedswitch which is'maintained closed by pressure in the welding gun returnline and opens upon the release thereof. rShe :opposite side of thepressure switch is connected through line YH32 with a point intermediateswitches Ai and L2. 'The two lines just to the left lof coils C -andDwhich are shown by arrows are connected into the selector switch on theweld timer. The inch and run'switch l5 is shunted by contactor M2.

CoilsA J andV K which are connected iniparallel are the coils primarilyintended to actuate the dynamic brake of the drive and have serially in'sequence the following switch contactors: H3, L54, PI, the lattercontact being opened when the press is not in motion and closed when itis in motion, and L3. Shunting contactor LSE is a second cam actuatedcontact LSS and shunting both contactors H3 and L54 is a contactor DI. Aholding circuit for relay coil A is provided around the run buttons 94through conductive line |94 which has in series relation threecontactors LSL LS and A2. The mechanical solenoid brake is set undernormal spring bias and the relay E is energized to remove the brakingpressure by closure of two contacts El and E2 which are in series withthe brake coil T. The three elements being in series across the lines 46and 48.

The relay coil M is the welding cycle initiating relay and when thiscoil is energized the welding machine proceeds through its normal cycleof welding, the press during this time remaining in stationary clampedposition. Serially connected with the relay coil M are the followingswitch contactors LSE, H5, Eil, P2, vopen when press is not in motionand closed when press-is in motion and N2. Connected at an intermediatepoint between switches H5 and E4 in this series connection is a line |95which extends to a control circuit from the welder indicated by the twodownwardly directed arrow tipped lines shunte'd by a switch m3 andthence to the lrelay coil N. This switch iii 'is a limiting switch whichis operated by the last contact ofthe Welder timer. In shunt around thiswelder controlled switch is a holding contactor N3. In series with therelay coil P between lines 46 and 48 is a controlling switch Hl which isoperated by the speed of the member driving the platen and is closed Vatlow speeds and opened at higher ones, such for example as those vaboveR. RM.

The power transformer ||2 which supplies'the power for the magneticclutch and brake' has its primary H4 connected across lines 40 and 42`of the power supply and has in series therewith two control contactorsD2 and C2 and in shunt relation around each of these contactors arefurther switch contactors Ki and JI respectively. The secondary HG ofthis 'transformer is center tapped and connected to line HB. One of theoutside terminals is connected through line 23 with a rectifier tube Silthe oppositesecondary terminal is connected through line |22 to a secondrectifier tube 92. Supplying the filament power for these rectifiertubes is a transformer |24 whose primary |25 is connected between lines4c and 42 and whose secondary |2B'has its two outside terminalsconnected to lines |30 and |32 wlfiichzextend` to the filament circuitsof tubes 90, 92.:and 88. Secondary |28'isalso center tapped andline |34connected thereto.

The operating coil'l36 for theelectromagnetic clutch is connecteddirectly between lines |341and |13 and has in series relation theretocoil S which'is provided with some time delay means, switch contactor D3and C3, on one side and a pair of torque limiting resistors |38 andswitch contactors C4 and D4 on the opposite side. The two torquelimiting resistors |38 are by-passed by va shunt circuit which includesswitch contactors H5 `and H4. The dynamic brake coil `on the other handshown at It!) is also connected between lines i3d and H8 and has inseries relation therewith on one side contactor J2 and' K2 and on theopposite sideKS and J3.

Figure 2 diagrammatically showsthe phased mechanical operation of thevarious cam operated switches, the shaded portions indicating the timeperiods ina complete cycle of rotation during which the switch'actuatedthereby is closed and the unshaded or clear portions that period of timeduring which that switch is open, a'full cycle of the ram being thusrepresented by a fiat `rectangle and showing that time during which themachine starts from its initial lowered position, is raised to clamp thewelding electrodes which are then fired and the platen lastly returnedto its lowermost position. The diagrams as will be noted are numberedfrom i to 9 and the switches in the circuit diagrams of Figs. 1 and 1Ahave been identified as LSL 2 or 3 as operated by cams i, 2 or 3 of-Fig.2.

In Figure 3, the motor 22 is shown provided with a pulley 23 driving arotatable flywheel 25 through a belt 21. The iiux generating coil |36 iscarried by the ilywheel. Rotatably mounted within the ywheel is a spider29 made of magnetizable material which is an integral part of a shaftsection 29. vA crank 3| is rigidly connected to the outer end of theshaft section and a link 33 is pivotally connected to the crank end andto a movablepart 35 of a machine or press which it is desired to driveor move. A friction brake 3l' is spring biased toengage the shaft to.prevent its rotation by spring 39 and may be moved away frombrakingposition by solenoid' E. The flux brake coil |40 is supported ona stationary drum`4| within the spider. Thus, with the iiywheelcontinuously rotating when coil |36 is energized, the spider will bedriven thereby through the flux linkage and when the coil |3 isdeenergized and coil IM! energized the spider willv have a brakingaction vapplied due to the stationary flux eld. The friction brake isoperated to vremove the brakingk action by energization of coil E inproper timed relation as will be further described.

The operation of the device will now'be 'explained in detail. Assumingthat the machine is de-energized and in a position of rest, which undernormal circumstances would be when the platten is lowered position readyfor the insertion of a part to be welded between the upper and Ylowerelectrodes, the switches all being shown, `either open or closed in theposition when its'operating coil is cle-energized. Switch is thenvvclosed which vappliespower to transformer Se. `The power circuit tothe driving motor 22 may be completed by closing of either Yswitch 56 or6| as the case may be depending upon whether the operator desires themotor to run vin one direction or the other.

Let us assume that it is desired to energize the motor so that it willrun in a forward direction, the operator then closes switch t whichcompletes an obvious circuit through coil F since all of the remainingcontactors in that circuit are normally closed by either safety switchesor interlock switches. The energization of coil F' therefore causes theF contacts in the power line to close and the motor 22 will rotate inthe forward direction.

Transformer H2 and transformer l2@ are now energized and until the tubese@ and Q2 have heated a predetermined length of time, none of theremainder of the control circuits may be energized. This is due to thefact that electronic thermal switch B8 will not permit the closure oftime delay switch contacts 3E.

Since, however, the motor is not clutched to the ram* drive no movementof the latter will be affected. In order to move the ram up into weldingposition the clutch must be energized. After a suflicient time periodhas passed to cause the thermionic time delay means S8 to conduct, itcloses switch 88 which in turn energizes relay coil L. Assuming furtherthat it is desired to run rather than inch the press, switch i6 is movedto its lower position completing the circuit through relay coil l-I andthat is therefore also energized.

This completes a circuit through relay coil A as follows: Power line 45,normally closed switches 62, 64, 63, l'ii, l2, lll, switch Hi, switch R6which is normally closed when relay coil R is de-energized, a series ofswitches 9e, coil A to power line 48. As soon as this circuit iscompleted, a holding circuit for relay coil A is provided through linelill, switches LSI, LS and contactor A2 which is now closed. Referringmomentarily to Fig. 2 it will be seen that cam controlled switches l andare closed at this time since the shaded portion of these diagramsbegins at the upper or zero position of rotation. Relay coil A beingenergized, Al is now closed, switch L2 has previously been closed assoon as the time delay contacts are closed as previously described, andswitch Ml is closed inasmuch as relay coil M is de-energized- As soontherefore as all the run buttons 9G are depressed by the operators,relay coil B will be energized through an obvious circuit which closesswitches Bl and B2 thus completing a circuit through relay coils C andD'. The reason for these two coils being connected in parallel andoperated simultaneously is strictly for safety reasons. Thus, ifcontacts operated by one freeze in, the other will still operate thecircuit normally since the contacts operated by the two are always inseries and the device will not assume any abnormal operation.

The energization of these two coils C and D opens contactor DI andcloses contactors CI, C2, D2, C3, D3, C4, and D4 to complete the powercircuit to the clutch coil I3 energizing the same. This magneticallylocks the motor to the press drive and the ram begins to ascend sincethe mechanical brake is also released by the energization of C and E. Ifthe clutch does not become energized, through a tube or brush failure,the series relay S,I does not pick up and consequently the Si contact inseries with relay El does not allow the spring set magnetic brake torelease. However, if current flows through the S relay the magneticbrake will release simultaneously with the closing of the contacts D3and C3, C4 and D4 and the press will operate through approximately ofrotation on the depression oi buttons 94, at which time cam number 2operating the LS2 switches will close which by-passes the run buttons 94which may then be released and the cam LSZ controls the rotation, asshown by the shaded portion in the middle of cam 2 on Fig. 2.

During the time the cam 2 takes over cam l allows its contacts LSI toopen cle-energizing relay coil A which provides an anti-repeat operationshould the run buttons still be depressed. This permits cam LSZ tocontrol the energization period of coils Cv and D and release them at apredetermined point slightly less than a When these coils arede-energized the magnetic clutch, of course, immediately ceases todrive. Just as the clutch is released the dynamic brake is energized bythe closing of the LSA contacts in series with the coils J and K, andacts to bring the moving member to rest. As the ram comes to rest LS@opens to set the magnetic brake and hold it. Therefore the dynamic brakestops the load and the mechanical brake holds it.

As previously described, the coil H is energized so that switch H3 willbe closed and also ccil L has been energized closing contacts L3.Therefore, when cam 4 reaches a predetermined point, Lsg` will closeenergizing coils J and K which, referring now to the bottom of Fig. 1A,completes an obvious circuit through the dynamic brake coil |40. Thiscombined braking action will bring the press to a stop between deadcenter and 10 ahead of this point and is controlled by the setting ofthe cam d. As soon as motion has ceased relay P opens due to the zerospeed switch l l E to de-energize the dynamic brake, the mechanicalbrake holding the device stationary.

In order to insure that the welding is actuated at the proper time it iscontrolled by the cam switch 5 which is closed only within the desiredrange. Therefore, the weld initiating relay M is controlled by contactLSE, the zero speed switch relay P and the magnetic brake relay E which,of course, control the operation of switches Eli and P2 in the seriescircuit, switch H5 being closed as previously described and N2 beingnormally closed upon coil de-energization as well as E4. Theenergization of coil M sets the normal welding cycle off and the weldingguns are red. To assure that welding pressure will be maintained on thework throughout the welding cycle, the shunt circuit around switch i6 isclosed by contactor M2 so that even if switch 7G is accidentally openedthe circuit will still be maintained. After the last gun is red acontact in the timer, switch |68, energizes relay N which immediatelycloses contactor N3 and completes an obvious holding circuit aroundswitch |63 to hold in relay N. vThis also causes switch N2 to open,de-energizing relay coil M, which completes the welding cycle. Theenergization of relay N also closes switch Nl which by-passes the runbuttons and starts the press on the down stroke or last half of thecycle. This completes a circuit for the energization of coil B throughline 96, switch NI, switch l, line |22, switch L2, relay coil B and thisreenergization of coil B closes contactors BI and B2 to again energizethe magnetic clutch coils C and D and in turn the magnetic brake relay Eto release that brake.

As previously described, this action clutches the drive motor 22 to thedriving means for the press releases the brake and the press begins todescend. After rotation of a-fewsdegrees beyond the welding position,cam 'I assumes control by the closure of cam operated switch LS? tomaintain energization of coils C and D, by-passing contactor Ni whichinitiated the movement. The press continues automatically to movekdownward until the clutch is de-energized by the opening of switch LSislightly ahead of its completion of 360. As the clutch releases thedynamic brake is energized by control or" contact DI or cam 9 Yin itsoperation through switch LS which by-passes or is in parallel withswitch LSfl in the circuit to coils J andK. This dynamic brake remainson until approximately the end of the cycle and the magnetic frictionbrake sets slightlyA prior thereto through action of camoperated switchLSB. When the press stops, the dynamic brake is released by the zerospeed switch H which de-energizes coil P `droppingoutcoils J and K andtheir associated contacts.

It might be mentioned at this point that there is'a second anti-repeatcam LS@ in serieswith the rst cam LSI to prevent re-energization of coilA1 and thus the continuation ofthe press past the 360 cycle. lf any ofthe buttonsttl are released during approximately the first 155'oftravel, the press will stop by action of the dynamic andAmechanicalbrakes, but if l55is past, cam LSZ takes -over and the presswill go through its operation. This operation oi pressing` the buttonsof course, is repeated each time itis desired to operate the pressWelder;

Assuming now that it is desired to inch the press rather than to drivethe same through a full cycle, switch 16 is placed on contact 'i8 foroperating position. The press rotation is then directly under the entirecontrol of the manually operated inch button 84 and whenever it isdepressed an obvious circuit through relay coils C and D will becompleted to energize the clutch s coil 36 and the press will be driven.However, in this case coil H is not energized and the bypass aroundlimiting resistors |38 remains open and the resistors are placed inseries with the magnetic clutch 35 to cut down the current owtherethrough to a smaller amount to reduce the flux so that the drivingforce will be less. Whenever the inch button is relased the brakes willbe immediately set. The welding sequence during inching operation willnot function since the relay M cannot be energized due to the fact thatthe contacter H5 remains open. The welding guns however can be actuatedmanually by the closing of a selector switch on the weld timer whichby-passes a switch operated by the coil M (not shown).

If it is desired to operate the motor in the reverse direction theswitch 6l instead of switch 56 is depressed and the motor will berotated in that direction. As soon as switch El is pressed to energizecoil R, hold in switch R5 will be closed to maintain the motor operatingin this direction. This action also causes switch Re to open, since thisis a switch which is normally closed. This opens the circuit for the runbuttons 94 and makes them inoperative. The magnetic clutch and solenoidbrake can now only be actuated by the inch switch 84, the clutch beingenergized and the brake released when switch 84 is closed and vice versawhen the same is released, since it controls the energization of coils Cand D.

We claim:

l. In a control system for a press, a source of power, a motorconnectable to said source, rotatable means for driving said press,magnetic iiux clutchmeans between themotorand the rotatabledrivingmeans, energizing coils mounted in ,the v,clutch means, dynamicflux brake `means associated with therotatable meansto stop the same, assecondseries of energizing coilsxforthe brake.- means,KVV a f solenoid?released friction brake applicable to the s rotatable means, switchingmeans foricontr-oiling.'the clutch andfbrakes to simultaneously energizethefuX-clutch-and re lease: the friction fbrake land at 'a differenttime to deenergize thelux clutchl and energize the brakes to stop therotatablemeansA including al.- ternate' ccntrol means to providecontinuous drive for the press through an` operating cycle orfto movef"at small distances as desired, and additional switching meansin a shuntcircuit to thealternatefcontrol means to maintain a continuousv circuitthrough a given portion of the cycle once it has been started.

2. ln a control system for a press, a source `of power, a motorconnectable to said source, rotatable means for driving said press,magnetic flux-clutch means'between the motor and the rotatable drivingmeans,l energizing coils mounted in the clutch means, dynamic flux brakemeans associated with the rotatable means to stop the same, a secondseries of energizing coils for the brake means, a solenoid releasedfriction brake applicablel to the rotatable means, switching means forcontrolling 'the clutch and brakes to simultaneously energize the fluxclutch andreie'ase'the friction brake and at a different time todeenergize the flux clutch and energize the brakes to stop the rotatablemeans, a master switch controlling the first-named switching means forcontinuous operation for a cycle of the press, a shunt circuit aroundthe master switch, and additional switching means in the shunt circuitto close the same during a portion of the cyclic operation to assurecontinued operation of the press even though the master switch may beopened.

3. In a control system for a cyclically operating press machine, asource of power, driving means connectable to said source, operatingmeans for the press, magnetic flux clutch means between the drivingmeans and the operating means, dynamic flux braking means applicable tothe operating means, mechanical solenoid brake means applicable to theoperating means, switching means for controlling the clutch and brakesto initially energize the iluX clutch and emove the magnetic brake atthe beginning of a cycle in moving from a position of rest, energize theux brake, deenergize the flux clutch and apply the friction brake whenthe press is in clamping position at an intermediate portion of thecycle, further switching means actuated at the termination of theclamping portion of the cycle to again cause actuation of the rstnamedswitching means to energize the flux clutch and remove the frictionbrake to return the apparatus to a position of rest, and a holdingcircuit for the further switching means to assure return to the restposition.

4. In a control system for a press, a source of power, a motorconnectable to said source, rotatable means for driving said press,magnetic ux clutch means between the motor and the rotatable drivingmeans, energizing coils mounted in the clutch means, dynamic fluxbraking means and mechanical solenoid braking means applicable to theoperating means, energizing coils in the ux braking means, combinationrelay and cam controlled switching means toenergize the iiux clutchcoils and remove the friction brake to cause the press to move from aposition of rest to a position slightly in advance of the clampingposition and then deenergize the iiux clutch, energize the flux brakeand then apply the friction brake to stop the press in clamping positionto perform work on a clamped part, additional switching means acutatedby the completion of the acts performed upon the clamped part to causethe clutch and brake control switching means to recycle to bring thepress back to a position of rest, and locking means for the additionalswitching means to assure return to the rest position.

5. In a control system for a press having a platen that moves from aposition of rest to full clamping position to clamp work members uponwhich acts are to be performed and then returned to rest position, asource of power, a motor connectable to said source, rotatable means fordriving the platen, magnetic flux clutch means connected between themotor and the rotatable driving means to couple the same, magnetic iiuxbrake means applicable to the rotatable means and solenoid frictionbrake means applicable to the driving means, switching means connectedbetween the source of power and the magnetic ux clutch and brake andsolenoid brake to energize and deenergize same in time relation to movethe platen to clamping position, hold it there for a predetermined timeuntil acts have been performed on the Work members and then move saidplaten back to a position of rest, said initiation of the movement backto rest position provided by the completion of the acts performed uponthe work and locking means to maintain operation until the platen hasreturned to rest.

WILLIAM DE LOHR BERRY.

STERLING G. VIGARS.

WILLIAM E. ADAMEK.

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